Features of identical twins. Identical and fraternal twins - what is the difference

The birth of twins is quite rare, as twins make up only 2% of newborns. When triplets are born, it becomes known throughout the city, since triplets are born even less often and already account for 2% of twins born.

Multiple pregnancies are different. Not all children born as a result of such a pregnancy are alike. There are identical and fraternal twins. Eternal twins are as similar to each other as any brother and sister. Despite the fact that they develop in the uterus at the same time, the difference in the time of their conception can be from several hours to several days. These twins develop from two fertilized eggs. They can be either the same or different gender. Identical twins are produced when a single egg is fertilized by one sperm, and as a result of division, independent embryos are subsequently formed.

So far, doctors cannot determine the reason for this behavior of the germ cell. Identical twins are so similar to each other that sometimes their own mother cannot tell them apart. Such twins are 5 times less common than fraternal twins, and boys predominate among them.

A special phenomenon is Siamese twins, who share some common organs or body parts. The reason for this phenomenon is that the splitting of the embryo into independent forms occurs later than during the birth of ordinary twins, at a time when the embryo is already partially formed. Siamese twins are extremely rare. They are born once in 10 million births.

Twin embryos are the most capricious

Rare cases of the birth of twins are partly due to the fact that not all of them take root in the very first days after birth. For a woman, this goes unnoticed, and she does not even realize that she was “slightly” pregnant with twins. It has been established that only one out of 10 cases of conception ends in a normal pregnancy and leads to childbirth. It is impossible to plan the birth of twins. But there are completely objective reasons that increase the likelihood of having two or more babies at the same time. Moreover, this only applies to fraternal twins, because the probability of having identical twins is always constant. On average, it is 3 cases per 1000 pregnancies.

Chances of conceiving fraternal twins

So, the age of the woman is of paramount importance. The older you are, the more hormones your body produces. And hormones stimulate the maturation of the egg, therefore, with an increase in the number of hormones, the likelihood of several eggs maturing at once, ready for fertilization, increases. Therefore, for women aged 35-39 years, there is a real chance of conceiving fraternal twins.

The production of the hormone is affected not only by age, but also by the length of daylight hours. The best time to conceive twins is spring, when the day lengthens and the sun begins to gently warm up.

Heredity is of great importance. So, if there are already twins in the family, then the probability of giving birth to another pair is quite high, but it decreases with the distance in time of the generation of twins.

The ability to conceive twins is passed on only through the female line. Men can pass it on to their daughters, but there is no noticeable frequency of twins in the offspring of men themselves.

There is also an influence of duration on the conception of twins. The greatest ability to give birth to twins is possessed by women whose menstrual cycle is very short - 20-21 days, as well as women with abnormalities in the development of the uterus, for example, with a septum in the uterine cavity or with a bicornuate, as if forked, uterus.

And finally, twins and even triplets are quite often born through artificial insemination. This also occurs due to the use of hormonal drugs that stimulate egg maturation and ovulation. The appearance of two or three children in a family after many years is not such a rare occurrence.

There is an inexplicable pattern of more frequent births of twins during various social upheavals and wars. Maybe nature cares so much about preserving man on earth.

Nina Bashkirova, “Planning a Child”

No one will argue that the birth of a child is a great happiness, greater than which can only be the birth of two children at the same time. For some, this comes as a surprise, while others have spent a lot of time and effort studying how twins are produced. And if earlier their birth was called a miracle, then modern reproductive technologies have greatly simplified this process.

How do you get twins?

To understand the likelihood of a woman having two children at the same time, you need to initially understand the mechanism of such conception:

twins or fraternal twins are the result of the simultaneous maturation and fertilization of a pair of eggs; another option for their appearance could be the fertilization of one egg by two sperm at the same time;
The answer to how identical twins are produced is the division of a fertilized egg into two parts (zygotes), each of which carries the same set of genes.

Why do you get twins?

This option of fertilization is in a constant process of study, since it is impossible to say exactly what forces the body to comply with all the conditions necessary for the birth of twins. However, some indirect factors were still established. For example:

The genetic side of the issue plays the biggest role. The chances of conceiving twins increase if this has happened in the woman’s family, and best of all, in both spouses.
The guarantee of the birth of twins is the completion of the IVF procedure. Under the watchful eye of an embryologist, the process of fertilization and embryo transfer occurs, the number of embryos that survive is unpredictable. Sometimes only one of them remains, or several survive. Then the woman herself chooses how many to keep.
The answer to how twins are obtained may well be a long course of using contraceptive hormonal drugs or medications that treat. As a result of this, the functions of the ovaries are stimulated, after which a pair of eggs may well mature at the same time. However, this does not mean at all that you can prescribe a similar course for yourself - this is fraught with bleeding and cysts in the ovaries.

How to promote the birth of twins or twins?

There are some medically unsubstantiated theories that can be used to provoke a woman’s body to produce several eggs ready for fertilization. For example:

You need to understand that neither the IVF method, nor even the most careful adherence to medical or traditional methods guarantees pregnancy with several fetuses. Get ready for a lot of money, time, nerves, and possible disappointment. Nature will definitely take over, no matter how hard you try to keep it under control.

Many couples try. Some people want the child to grow up with a brother or sister of the same age. And others simply want to start a big family right away. Despite the fact that twins are born quite rarely, there are certain factors that can significantly increase the likelihood of two babies being born at the same time.

What determines the birth of twins? Factors such as lifestyle, genetic predisposition and even the ethnicity of partners come first here. If a married couple is determined to have twins, the following information may be quite useful.

What are twins like?

The birth of twins is determined by the type of fertilization of the maternal egg. The most common are dizygotic and In the first case, embryos appear from two different eggs during simultaneous fertilization. Children conceived in this way usually have both external and sexual differences.

As for monozygotic twins, their conception occurs as a result of the splitting of one fertilized egg into two equal parts. The development of a monozygotic fetus is always characterized by the birth of children of the same sex with an identical set of genetic characteristics, the same blood type and almost one hundred percent external similarity.

Reasons for having twins

The main reason for the development of two embryos at once with the natural method of conception is the abundance of healthy, highly active sperm in a man and the presence of an egg ready for fertilization. The effect is enhanced by unquestioningly following the recommendations of a specialist, maintaining a healthy lifestyle, as well as a predisposition to conceiving several babies in one or both partners.

Other reasons for the birth of twins are the consumption of foods or drugs whose constituent elements cause hyperovulation. However, doctors extremely rarely recommend these kinds of drugs in order to avoid the occurrence of various kinds of complications during pregnancy, although they are quite effective.

Genetic predisposition

There is an increased likelihood of several babies being born at the same time in families in which similar cases have been recorded on the maternal side. So, if a woman’s mother or grandmother gave birth to twins, she has an increased chance of also giving birth to twins.

However, it is not so simple. In this case, the combination of it in both partners is of great importance. More often, heredity in terms of the birth of twins manifests itself after one generation. But even with the combination of the above circumstances, the chance of a successful outcome of conceiving twins is no more than fifty percent.

With weak heredity or insufficient strength of sex hormones of partners, the probability of having twins or twins varies from five to fifteen percent.

Factors contributing to the birth of two or more babies at once

Statistics show that the chances of having twins or twins in a healthy woman without a genetic predisposition are only about three percent. In general, there are a number of factors, the presence of which increases the likelihood of two or more babies being born at the same time.

The likelihood of having twins increases if:

there have already been cases of the birth of twins or twins in the maternal family;
the woman has African roots (European women are second in the likelihood of having twins, followed by Asian and Latin women);
the woman has already had successful pregnancies (this trend is associated with the increased capabilities of the human body);
the woman is tall, leads a healthy lifestyle, eats well, or is somewhat overweight.

Nutrition and vitamins

In families in which partners lead an unhealthy lifestyle, eat poorly and neglect to consume food rich in vitamins and beneficial microelements, the likelihood of having twins is significantly reduced.

When conceiving a child and directly during pregnancy, any vitamin complexes are useful. However, as practice shows, the birth of twins becomes more likely with the active intake of food supplements with a high content of folic acid, which today can be purchased at almost any pharmacy.

Good, nutritious nutrition, rich in fresh, organic products, not only leads to the birth of a healthy child, but also increases the chance of having twins. These chances are significantly lower for people who are underweight.

If we talk about nutritious, good nutrition, then it should ensure uniform weight gain without causing harm to health and one’s own well-being. Naturally, when trying to increase the likelihood of having twins by any means, it is better to undergo a consultation in advance at a reputable clinic. After all, only the application of the knowledge of a trained, experienced and practicing doctor makes it possible to hope for a positive result.

What is the probability of having twins if you seek the help of a specialist?

Contacting an experienced specialist can increase the likelihood of conceiving twins. In modern medical practice, there are enough professional doctors who can help almost any couple give birth to twins.

Currently, issues of conceiving twins are most often resolved by using the method of in vitro fertilization. Conceiving children in this way can be expensive for a young couple. However, the artificial introduction of several healthy sperm into the mother's egg at the same time significantly increases the likelihood of achieving the desired goal.

Finally

What determines the birth of twins? This issue is still not fully understood and remains shrouded in mystery. However, it is certainly known that the increased likelihood of conceiving two or more babies is transmitted through generations.

It is worth noting that there are a sufficient number of families in which there are cases of conceiving several twins, twins and even triplets. There are also families where grandparents, cousins, nephews and nieces are twins. Therefore, nature knows the answer to this question best. All the best!

Twin embryos are the most capricious

The rare cases of twin births are partly due to the fact that not all of them take root in the very first days after conception. For a woman, this goes unnoticed, and she does not even realize that she was “slightly” pregnant with twins. It has been established that only one out of 10 cases of conception ends in a normal pregnancy and leads to childbirth. It is impossible to plan the birth of twins. But there are completely objective reasons that increase the likelihood of having two or more babies at the same time. Moreover, this only applies to fraternal twins, because the probability of having identical twins is always constant. On average, it is 3 cases per 1000 pregnancies.

Chances of conceiving fraternal twins

The ability to conceive twins is passed on only through the female line. Men can pass it on to their daughters, but there is no noticeable frequency of twins in the offspring of men themselves.

There is also an influence of the duration of the menstrual cycle on the conception of twins. The greatest ability to give birth to twins is possessed by women whose menstrual cycle is very short - 20-21 days, as well as women with abnormalities in the development of the uterus, for example, with a septum in the uterine cavity or with a bicornuate, as if forked, uterus.

There is an inexplicable pattern of more frequent births of twins during various social upheavals and wars. Maybe nature cares so much about preserving man on earth.

Twins are two or more children born during one multiple pregnancy and born to the same mother.

According to the number of twins there are: twins - two twins, triplets - three twins, quadruplets, etc.

By type, twins can be divided into two most popular types: monozygotic twins, or also called identical, identical, or, quite simply, real, similar twins, and dizygotic (fraternal) twins, which are popularly called dissimilar twins or simply twins.

The prefix “Mono” means that children come from one fertilized egg (zygote), and “Di” in our case means that twins develop from two separate fertilized eggs (zygotes).

Let's look at what types of twins there are, using the example of twins - that is, two twins, as the most common option. Well, let’s just play around a little bit with the variants of zygosity in triplets, quadruplets and even septuplets

Twins

Difference between twins and twins

The most successful and most common type of twins, which accounts for about two-thirds of all multiple twin pregnancies, are dizygotic dichorionic twins - in common parlance - fraternal twins. These babies are born as a result of the fertilization of two different eggs by two different sperm. With this type of twins, each child develops in his own house - in his own amniotic sac and has his own kitchen and energy supply - his own placenta.

Almost all dizygotic twins (except in very rare cases of fusion of their blastocyst) will be called dizygotic dichorionic (two placentas) twins. And, a moment of attention, friends, please, according to modern research, in 18-36% of monozygotic (identical) twins will also have two placentas and two amniotic sacs. This happens when one zygote (fertilized egg) splits into two separate embryos within the first 72 hours after fertilization.

In this case, each of the twins will develop in their own separate amniotic sac (fetal bladder) and will have their own separate placenta. And your initially identical twins will also be called dizygotic dichorionic twins by obstetricians at birth and by counting placentas and amniotic sacs.

Dizygotic dichorionic twins can be of the same or opposite sex. Most often, twins have quite large external differences because they are not genetically identical and their DNA is about 50% similar, that is, like ordinary brothers and sisters. And brothers and sisters can be both very different and very similar, you yourself know. Twins are of interest to biomedical research because they are children of the same age, born at the same time, and typically raised in the same environment.

The appearance of the most common type of twins - fraternal twins - is currently explained by hyperovulation, which can be natural, spontaneous, stimulated by drugs, or inherited from generation to generation, but only happens in women.

Twins

Identical twins are the result of one fertilized egg splitting into two. They are genetically similar and in the vast majority of cases the same sex. At the beginning of the first trimester, ultrasound can identify about two-thirds of monozygotic twins. There is evidence that the likelihood of conceiving identical twins is twice as high for couples who have undergone assisted reproductive procedures. Although the information has not been thoroughly confirmed.

Because identical twins are genetically very similar and typically grow up and are raised together, researchers love to study the similarities and differences between twins to advance the psychiatric and life sciences. Why is it that genetically and outwardly very similar people are completely different, unique individuals. And sometimes it happens that identical individuals even differ significantly in appearance and have different susceptibility to diseases.

Monochorionic diamniotic twins

Monochorionic diamniotic twins are monozygotic (identical) twins with one placenta and two membranes (amniotic sacs).

This type of monozygotic (identical) twins occurs most often - in 60-70% of multiple monozygotic twin pregnancies and in 0.03% of all pregnancies. Monochorionic diamniotic twins are almost always monozygotic, with some rare exceptions in cases of blastocyst division. With this type of twins, the fertilized egg divides 4 to 8 days after conception.

Monochorionic monoamniotic twins

Monochorionic monoamniotic twins are identical twins with one placenta and one amniotic sac. With this type of twins, the fertilized egg (zygote) divides into two from 8 to 12 days. This is a fairly rare type of twins - 1 - 2% of all monozygotic twins. Here, babies are no longer as comfortable as in the two previous types due to cramped living conditions in one common amniotic sac in the mother’s womb. Little twins develop and grow in the same amniotic fluid; there is no septum between them and therefore there is an increased likelihood of entangling the other baby with the umbilical cord and problems with the oxygen supply. Therefore, if you have this type of twins, then you should take special care of your health and preserve yourself in the best possible ways. And then everything will be fine for you.

Siamese twins

I would like to avoid this most rare type of twins. They often like to scare already impressionable expectant mothers, but on the contrary, they want to reassure that it occurs in only 0.5% of all monozygotic twins and occurs because the division of the fertilized egg occurs on the 12-13th day after fertilization. With this type of monochorionic monoamniotic twins, the children will be in the same amniotic sac (fetal sac), share the same placenta and are connected by separate body parts. Conjoined twins occur in 1 in 40,000 births. That is, extremely rarely.

So, dear friends, twins are everyone who has more than two from their mother: both twins and triplets. That is, twins are twins, and twins are twins.

And already twins come from one egg or from two separate ones, which gives a strong similarity or strong difference between the children. With rare exceptions, about which you read a little higher.